Crimped string retainer for excavating tooth



P 1968 G. A. PETERSEN 3,400,476

CRIMPED STRING RETAINER FOR EXCAVATING TOOTH Filed July 12, 1965 i l l INVENTOR. GERALD A. PETERSEN BY QLW Q24: ATTORNEY United States Patent 3,400,476 CRIMPED STRING RETAINER FOR EXCAVATING TOOTH Gerald A. Petersen, Sunnyvale, Calif., assignor of onehalf to Anita E. Petersen, Saratoga, Calif. Filed July 12, 1965, Ser. No. 471,110 3 Claims. (Cl, 37-142) ABSTRACT OF THE DISCLOSURE A pronged tooth of the type of Patent No. 2,968,880 is formed with a notch in at least one wall of the proximal slot. The web of a tooth-holder of the type of said patent receives a metal spring formed in a bow shape which fits through the hole in the web. The spring is formed with a crimp which engages the notch and prevents unintentional dislodgement of the tooth from the toothholder.

This invention relates to a new and improved crimped spring retainer for excavating tooth of the type used in earth angers, trenching machines, and similar digging equipment. Essentially this invention comprises a modification of the means for retaining a tooth of the type shown in Patent No. 2,968,880, in its holder.

In the aforementioned patent, means is shown for securing an earth-digging tooth to a toothholder, attached to digging equipment or directly to the digging equipment itself. In such patent the proximal portion of the tooth is divided into two substantially rectangular cross section prongs extending longitudinally of the tooth. The toothholder has forwardly-opening recesses shaped to receive the prongs and separated by a web which fits into the slot defining the prongs. Thus, such holder resembles the letter H turned on its side. In accordance with this invention a hole is formed through the web to receive a section of spring stock of the type of flat watch spring, which spring stock is crirnped. The spring is bent back between the web and the walls of the slot and the walls of the slot are notched to receive the crimped portions of the spring. Thus the spring retains the tooth in its holder. When it is necessary to remove the tooth for sharpening or replacement the spring is sutlieiently deformable so that a force applied to the rear of the tooth will temporarily flatten the crimps to permit withdrawal of the tooth.

Accordingly, the present invention provides an adequate means for retaining the tooth in its holder against normal stresses encountered during digging action but which is capable of being overcome when it is required to remove the tooth.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is a top plan of tooth and holder, the holder being partly broken away in section.

FIG. 2 is a longitudinal sectional view taken substantially along the line 2-2 of FIG. 1.

FIG. 3 is a transverse sectional view taken substantially along the line 2-2 of FIG. 1.

FIG. 4 is an exploded perspective view of the tooth, a portion of the holder, and the spring retainer.

FIG. 5 is a plan view of the spring before installation.

The proximal portion of tooth 11 resembles that shown in Patent No. 2,968,880, having proximal prongs or roots 12 on either side of the tooth each substantially rectangu- Patented Sept. 10, 1968 ice lar in cross-section and extending longitudinally from the read ends 13 of the prong and defined by a slot 14 having substantially vertical side walls 16 and a forward end 17. One or more vertical notches 18 are formed in each of side walls 16. Top and bottom surfaces 19, 21, are preferably flat and parallel and the side "edges 22 of the tooth are substantially vertical and parallel.

The distal portion of tooth 11 has side edges 23 which are continuations of edges 22 and broad substantially fiat forwardly-converging top and bottom surfaces 24, '26, which terminate in a blunt truncated forward end 27. In the form .of the invention herein illustrated, transverse humps 28 are formed on surfaces 24, 2-6, at the juncture of the distal and proximal portions and immediately forwardly of toothholder 31. Humps 28 are optional but when used assist in preventing abrasion of holder 31.

Holder 31 has top and bottom flanges 32, 33, interconnected by a vertical web 34 having a front end 36 which abuts the forward end 17 of slot 14. The distance between top and bottom walls 37, 38, of flanges 32, 33, respectively, is about the same as the distance between surfaces 19, 21, and the width of web 34 is approximately equal to the width of slot 14. A transverse hole 39 is formed in web 34 adjacent the forward end thereof. At the rear of web 34 are openings 41 forthe purpose of knocking the tooth out of its holder and preferably shoulders 42 are formed in the back of web 34 for a purpose which hereinafter appears.

Spring 46 is formed of flat stock similar to a clock spring and is dimensioned to fit through hole 39 in web 34. Initially spring 46 is bow shaped as shown in FIG. 5, having a central portion 45 and legs 49 to either side of portion 45. Crimps 47 are formed in legs 49 to fit into notches '18 in walls 16. Inward turned ends 48 are formed on the opposite ends of legs 49 to fit behind shoulders 42.

In use, the spring 46 is inserted so that center 45 is in hole 39 and legs 49 extend out to either side of web 34 as is shown in FIG. 4. Tooth 11 is forced rearward with prongs 12 fitting into the openings between surfaces 38, 39, to either side of web 34 until end 36 seats against shoulder 17. This bends spring 46 back to the position best shown in FIG. 1 with ends 48 behind shoulders 42 and crimps 47 in notches 18. In such position spring 46 holds tooth 11 in holder 31 against all normal forces tending to dislodge it. However, when it is necessary to remove the tooth, an instrument is inserted through one of the openings 41 to drive the rear end 13 of the tooth forwardly, thereby deforming the crimps 47 in spring 46 and allowing the tooth to slip out of its holder.

What is claimed is:

1. In combination, a tooth having a distal portion formed with at least one cutting edge and a proximal portion having longitudinally parallel top and bottom surfaces and a slot extending from top to bottom forward from the proximal end of said tooth to divide said tooth into two prongs, said tooth having a first wall facing inwardly of said slot formed with at least one notch; a tooth-holder having a forwardly facing recess complementary to said proximal portion and having a web complemetary to said slot, having a second wall parallel and in proximity to said first wall and a transverse hole at its forward end; a retainer formed of metallic spring stock fitting through said hole and back between said prongs and said web and between said first and second walls, said retainer formed with at least one permanent crimp fitting into said first notch, said protuberance normally restraining unintentional withdrawal of said tooth from said holder and deformable to permit intentional withdrawal of said tooth by driving said tooth forward, said retainer 3 being formed with inwardly turned ends and said web being cut away to form shoulders engaging said ends to limit forward movement of the free rearward ends of said retainer.

2. The combination of claim 1 in which said first wall is formed with a plurality of longitudinally spaced notches and said retainer with a corresponding plurality of 1ongi- 'tudinally spaced crimps.

3. The combination of claim 1 in which notches are tainer to fit said notches.

References Cited UNITED STATES PATENTS ABRAHAM G. STONE, Primary Examiner.

formed in both walls of said slot and crimps on said re- 10 ANTONIO GUIDA Examiner A. E. KOPECKI, Assistant Examiner. 

